Flashcards in Myocardial Infarction - Johnston Deck (44):
Inverted T waves
- Chest leads (closest to ventricles)
Causes of MI (occlusion)
Chest pain, etc. not relieved by nitro or rest...Think what?
Silent MI...think what?
Diabetics, elderly women
4 signs of new heart failure
- S3 gallop
- Crackles in lungs
- Increased JVD
- New murmur
Autonomic responses for...
Anterior MI vs. Inferior MI
Anterior - sympathetic (tachy, HTN)
Inferior - parasympathetic (bradycardia, hypotension)
EKG signs of STEMI
- Men - > 2mm STE (V2-V3)
- Women - > 1.5mm STE (2 or more contiguous leads)
- Maybe new LBBB
NSTEMI or NST ACS - EKG
ST depression, T wave inversion
Distinguishing NSTEMI from NSTE ACS
NSTEMI - elevated cardiac enzymes
NSTE ACS (angina) - normal cardiac enzymes
Early phase of STEMI - EKG
What are they?
Tall hyperacute T waves
- Upward, slightly curved pattern
Causes of inverted T waves (7)
- Normal in children (V1-3)
- Myocardial ischemia
- Ventricular hyper. w/ strain
- Hypertrophic cardiomy.
- Raised ICP
How to tell where the acute MI is occurring?
Where are the inverted T waves?
- Inferior = 2, 3, F
- Lateral = 1, L, V5-6
- Anterior = V2-6
ANY T-wave inversion in leads _____ is considered pathological
Other causes of STE?
- LVH w/ J point elevation
- Normal variant early repol.
Pericarditis - EKG
ST segment elevation, usually flat or slightly concave, with potentially the whole T wave elevated to the next P wave
Causes of ST depression?
- Subendocardial ischemia
- Stress test
- Digitalis toxicity
Diagnostic feature for infarction on EKG
Significant Q waves (NECROSIS) in the infarcted area leads
What is a "significant" Q wave?
> 1mm wide or 1/3 the QRS amplitude tall
A normal Q wave in leads ___ is INSIGNIFICANT
SO, 3 things to look for when suspecting MI?
- Significant Q waves
- STE or ST depression
- Inverted T waves
Describe why a Q wave means necrosis?
If the cardiac tissue under the lead is necrotic, there is no electrical activity, so the lead picks up the septal impulse moving away towards the other ventricle
ST elevation in terms of MI means what?
How to detect an acute posterior infarction?
The OPPOSITE is true of that in an ANTERIOR MI...
- in V1-2, QRS is "flipped"
- in V1-2, R wave is up
- "STE" --> ST depression
Significant Q in 1 and AVL
Significant Q in V1-V4
Significant Q in 2, 3, F
Large R in V1, V2
Signs of MI can be obscured by ____
Persistent ST elevation (over 2 weeks)
Ventricular aneurysm (after an MI)
Standard care for STEMI
- EKG and continuous cardiac monitoring
- IVs inserted
- Cardiac enzymes, blood panels, clotting times
- Reperfusion, fibrinolysis
- Heparin, MONA
How to monitor reperfusion therapy?
Must see resolving ST elevation within 1-2 hours
Major risk factor for fibrinolytic therapy
Good times to use fibrinolysis
STEMI or new LBBB (within 12 hours)
When to use a beta blocker in heart failure or MI?
If BP or HR are elevated due to compensatory response
When to use an ACEI in HF or MI?
If EF is low or BP is high
Previous Hx of MI, now hurts to breathe and feels better leaning forward
Dressler syndrome (immune-mediated)
Previous MI --> fibrinolytic therapy --> ventricular tachycardia
Accelerated idioventricular rhythm (AIVR)
Arrhythmias associated w/ inferior MI
Sinus bradycardia, Wenckebach AV block
Differential diagnosis for a STEMI
- Takotsubo (stress-induced) syndrome
- Early repolarization
Initial pharma treatments for STEMI
- Aspirin (unless contraindicated)
- IV Heparin or antiplatelet agent
Full pharma list of treatments for STEMI
- BB - IF high BP or high HR
- Stool softener
- ACEI - IF low EF or high BP
- Thrombolytic therapy
Most common rhythm disturbances after an MI
What can occur on EKG after fibrinolytic therapy? Serious?
Slow V tach (60-100)